Signaling system



March 25, 1924. 1,488,207

s. w.v KUHN ET AL SIGNALING SYSTEM Filed Jan. 30, 1920 Q ng WWW F lw- I N V EN TORS.

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GEORGE W. KUI'IN AND ROGER G. RAMSDEL-L, OF BROOKLYN, NEW YORK, ASSIGNOBS TO AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK.

SIGNALING SYSTEIVI.

Application filed January 30, 1920. Serial No. 355,175.

To all whom, it may concern:

Be it known that we, GEORGE W. KUHN and Bosnr. G. RnMsDnLL, residing at Brooklyn, in the county of Kings and State of New York, have invented certain Improvements in Signaling Systems, of which the following is a specification.

This invention relates to improvements in signaling systems and more particularly to that type of signaling system which is adapted to apply to a subscribers telephone line upon which the receiver has inadvertently or otherwise been left off its hook, a potential of varying magnitude which causes the receiver to produce a tone designed to attract the attention of the subscriber and thereby to effect the restoration of the receiver to its normal idle position upon the hook.

In the Patent No. 1,279,882, which issued to G. W. Kuhn on September 2 1, 1918, there was disclosed a howler system adapted to apply a potential of varying magnitude to a subscribers line and designed to effect the application of the said potential to the line only at the instant when the potential was of minimum magnitude. In the arrangement disclosed in the above patent and in other howler circuits heretobefore used, no automatic means are provided to disconnect the source of varying potential from the circuit after the receiver has been restored to its hook and to prevent its reconnection to the circuit in case any subscriber on the line removes his receiver from its hook thereafter but prior to the instant of disconnection from the subscribers circuit of the source of howler potential by the operator responsible for such action. Thus if the operator failed to act promptly upon receiving the disconnect signal when the subscribers receiver, inadvertently left off its hook, has been restored thereto, the howler circuit would continue to apply its varying potential to the line and since this is liable to produce a signaling tone in any receiver removed from its hook on this line, it is objectionable from an operating standpoint.

It is one of the objects of this invention to provide means whereby the source of varying electromotive force will be auto matically disconnected from the line whenever a receiver, inadvertently left off its hook, has been restored thereto. It is a. further object of this invention to prevent the reconnection of the said source of electromotive force to the line in case a receiver of a telephone set on the same line is subsequently taken from its hook prior to the disconnection of the source of howler potential from the said line.

This invention will be made clear by the following description of the invention and its mode of operation when read in connection with the attached drawing showing one embodiment of the invention.

In the drawing L represents a subscribers line having connected therewith two subscribers stations A and A the former of which station is represented with the receiver removed from its hook. Associated with the line L, are a line relay R and a cut-off relay R The line L may ter minate at the switchboard in a jack J, as shown into which may be inserted the plug P, of the howler cord circuit. Associated with the. howler cord circuit is a. key K, which when operated to the left connects the leads of the operators telephone set with the cord circuit and when operated toward the right serves to connect the source of varying electro-motive force with the windings of the transformer T Connected with the cord circuit are a supervisory relay R,,, a. control relay It and a. lamp 5. The source of tone G, connected with the former T primary winding of the transmay be of any well known type adapted tocreate a varying electromotive force. The circuit containing the generator G and the primary winding of the transformer T is adapted to be closed by the operation of the relay and may be opened by the operation of the relay R which operations will be more fully described hereafter. The secondary winding of the transformer T is connected by means of a plurality of taps with a plurality of segments of the communicating device 1. This commutating device has associated therewith a grounded arm 2 which supports a brush 3 adapted in the course of rotation of the. arm 2 to make contact successively with the various segments of the commutating device. One of the segments 4 of the commutating device is not connected with the secondary winding of transformer' T but is connected with the circuit of the controlling relays andthe function of this segment is to provide one of the means by in its right hand position. The only effect of the removal of a receiver from its hook at station A, or A subsequent to the restoration of the receiver at fault to its hook is to operate the relay R which in turn oper" ates the relay R, opening its contact 15 and closing its contact 9. It will be seen that the locking relay R, is no longer dependent upon contact 15 to ensure its re maining in an operated position, but remains locked over contacts 17 and 16 to ground. The primary circuit of the howler circuit will therefore remain open and no potential will be impressed upon the telephone linc, even though the howler cord circuit remains connected with the line L If the subscriber at station A, or A moves the hook switch up and down, the operator at the trouble position will have her attention attr cted by the flashing of the lamp 5. She will accordingly move the key K,-

to its left hand position and finding that the party desires to establish a telephone connection, the operator will withdraw the plug P, from the jack J,, the desired connection will be established by a regular cord circuit in the usual manner.

From the foregoing description, it will be apparent that this invent-ion covers a signaling system of the howler type which is adapted to apply a potential of gradual- 1y varying magnitude to a telephone line upon which a receiver has been left off its hook, inadvertently or otherwise, and is designed and intended to automatically disconnect the source of varying potential from the line as soon as the receiver at fault is restored to its hook. The principal result of such automatic control of the source of howler potential is to limit to a minimum the period of application of the said potential to the line, which is decidedly advantageous in the case of party lines since such control reduces correspondingly the period of time during which a line is rendered useless from a transmission standpoint by the application of the howler potential thereto. Furthermore, it will be seen that the means described eifectively lock open the circuit containing the said source of signaling energy and prevent therefore its accidental application to the line in case a receiver at any subscribers station on this line he removed from its hook after the disconnection of the source of howler potential. from the line.

Although this invention has been described as embodied in a howler circuit at the trouble position of a switchboard, it is to be understood, that it is not thus limited but may be used whenever and wherever in the application of a sorce of signaling electromotive force to a line it is desired that the control of the connection of the said source with the said line shall be dependent upon circuit conditions at a point remote from the said source.

And, furthermore, although this invention has been shown as embodied in a definite, specific form, it is to be understood that it is not intended to so limit it since it is capable of embodiment in other aid different forms from that shown within the scope of the appended claims.

What is claimed is:

1. In a signaling system, the combination of a telephone line having associated there with a substation set in its operated position, a source of signaling potential, means for connecting said source with said line at the instant of minimum potential. means for disconnecting automatically said source from said line when said substation set is restored to its normal nonoperated position, and means for automatically preventing the reconnection of the said source if the said substation set is subsequently operated.

2. In a signaling system, the combination of a telephone line having associated there with a substation set in its operated position, asource of signaling potential. means for connecting said source with said line to produce an audible tone in the receiver of said set, means for automatically disconnecting and for maintaining disconnected the said source from said line, whenever said substation set has been restored to its normal nonoperated position and means to indicate the position of said substation set.

3. In a signaling system. the combination of a subscribers line having connected therewith a plurality of substation sets one of said sets having its receiver removed from its hook, a cord circuit having a source of signaling potential associated therewith, means to connect said cord circuit with said line, when the said potential is at the point of minimum. intensity, switching means associated with said cord circuit and automatically controlled by the restoration to its hook of the receiver at fault to effectively disconnect said source of potential from said line and locking means to prevent the reconnection of said source in event of the subsequent removal of a receiver from its hook at any of said stations.

4. In a signaling system, the combination of a telephone line having connected therewith a plurality of substation sets one of which is in operated position. a cord circuit having a source of signaling potential associated therewith, means to connect said cord circuit with said line, switching means for connecting said source to said line at the instant of minimum potential and means for'automat-ically rendering said source ineffective as soon as the said one of said substation sets is restored to its nonoperated position thereby reducing to a minimum the period during which other parties are lit prevented from using said line on account of the application thereto of said signaling potential.

In a signaling system the coniliiination with a suhs rihefs telephone line in ope:- ated position and a signaling circuit adapted to be connected with the said telephone line and comprising source ot varying potential, means tor applying the said potential to the said telephone line only when the potential is its minimum value, means to effect the rcmov l the said potential the said line i the latter has seen to automatically prevent the reapplication oi the said potential it the said subscrihers line is subsequently operated.

6. In telephone howler system comprising a suhscrihers line having a subscribers telephone set connected thereto, the

receiver of which is connected so as to he currents transmitted thereover, a source of varying potential and a plurality of switching means for controlling the connection and disconnection of the said source with the said line, the method which consists in applying a varying potential to the said line, discontinuing the application of the said potential to the line as soon as the said receiver is effectively disconnected from the said line, and automatically preventing the rc-application of the said potential upon \esequent re-c nnection of the said receiver with the said line.

8. In a telephone howler system, the combination with a suhscrihers line having a subscribers telephone set connected thereto, the receiver of which is so connected as to be affected by currents transmitted thereover, of a source of varying potential, switching means initially controlled manually to automatically connect the said source with the said line, switching means to automatically disconnect the said source from the said line when the said receiver is effectively disconnected from the said line, and locking means to automatically prevent the re-con nection of th said source with the said line when the said receiver is again re-connected with the said line.

In testimony whereof, We have signed our names to this specification this 28th day of January, 1920.

GEORGE W. KUHN. noenn e. nansnnnn 

